Assembly wrenches are increasingly being used for tightening screw connections using a specified torque, which besides, or instead of a conventional display of the torque exerted upon the screw joint, have an integrated angular measuring device and an angular measuring display, in order to measure and display the angle by which the assembly wrench has been rotated.
When using such assembly wrenches, it is possible, by pretightening the screw connection using a light torque, and subsequently rotating the assembly wrench by a specified angle of rotation, to produce screw connections in which the prestressing force of the screw connection moves within a lesser tolerance range than when tightening using a conventional torque wrench, which displays the starting torque applied or, upon exceeding a specified starting torque, “slips”.
In order to ensure a constant quality of the screw connections thus produced, regular checking is required and possibly the calibration of the angular measuring device that is integrated in the assembly wrench.
It is believed that the methods up to now, for checking and calibrating such assembly wrenches either require too much. effort, are tedious and costly, such as sending them in to the manufacturer, or do not have the requisite accuracy, such as checking the angle display with so-called angle disks.